U.S. patent application number 16/119513 was filed with the patent office on 2020-03-05 for valves, valve assemblies and applications thereof.
The applicant listed for this patent is Kennametal Inc.. Invention is credited to Keith BROCK, Grzegorz DEWICKI, Ranjith Seenappa, Joshua M. SINGLEY.
Application Number | 20200072368 16/119513 |
Document ID | / |
Family ID | 69526931 |
Filed Date | 2020-03-05 |
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United States Patent
Application |
20200072368 |
Kind Code |
A1 |
SINGLEY; Joshua M. ; et
al. |
March 5, 2020 |
VALVES, VALVE ASSEMBLIES AND APPLICATIONS THEREOF
Abstract
Valves and valve assemblies are described herein employing
architectures which can mitigate degradative wear mechanisms,
thereby prolonging life of the assembly. In one aspect, a valve
comprises a head including a circumferential surface and a valve
seat mating surface. Leg members extend from the head, wherein
thickness of one or more of the leg members tapers in a direction
away from the head to induce laminar fluid flow around the head.
The valve can also comprise a seal coupled to the circumferential
surface of the head. In some embodiments, an exterior surface of
the seal exhibits a radius of curvature maintaining laminar fluid
flow around the valve. Additionally, the seal can overlap a portion
of the valve seat mating surface, in some embodiments.
Inventors: |
SINGLEY; Joshua M.;
(Latrobe, PA) ; DEWICKI; Grzegorz; (Greensburg,
PA) ; BROCK; Keith; (Sellersburg, IN) ;
Seenappa; Ranjith; (Bangalore, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kennametal Inc. |
Latrobe |
PA |
US |
|
|
Family ID: |
69526931 |
Appl. No.: |
16/119513 |
Filed: |
August 31, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K 25/00 20130101;
F16K 1/36 20130101; F16K 1/12 20130101 |
International
Class: |
F16K 25/00 20060101
F16K025/00 |
Claims
1. A valve comprising: a head including a circumferential surface
and a valve seat mating surface; and leg members extending from the
head, wherein thickness of one or more of the leg members tapers in
a direction away from the head to produce laminar fluid flow around
the head.
2. The valve of claim 1, wherein an intermediate body member is
positioned between the head and leg members.
3. The valve of claim 1, wherein a transition region between the
intermediate body member and the head has a radius of curvature of
0.5 mm to 5 mm.
4. The valve of claim 1 further comprising a seal coupled to the
circumferential surface of the head.
5. The valve of claim 4, wherein the circumferential surface
defines an annular groove engaging the seal, the annular groove
having a top surface and bottom surface.
6. The valve of claim 5, wherein the top surface of the annular
groove extends radially beyond the bottom surface.
7. The valve of claim 6, wherein the bottom surface transitions to
the valve seat mating surface.
8. The valve of claim 7, wherein the transition of the bottom
surface to the valve mating surface has a radius of curvature less
than the annular groove radius of curvature.
9. The valve of claim 4, wherein an exterior surface of the seal
exhibits a radius of curvature maintaining the laminar fluid flow
around the valve.
10. The valve of claim 4, wherein the seal forms an angle with the
valve seat mating surface ranging from 5 degrees to 30 degrees.
11. The valve of claim 10, wherein the angle ranges from 10 degrees
to 20 degrees.
12. The valve of claim 10, wherein the angle establishes a primary
seat contact area on the seal.
13. The valve of claim 12, wherein the primary seat contact area is
proximate an outer circumferential surface of the seal.
14. The valve of claim 13, wherein compressive stress is
concentrated at the primary seat contact area when the valve is
mated to a valve seat.
15. The valve of claim 1, wherein the valve seat mating surface
comprises an alloy cladding.
16. The valve of claim 15, wherein the cladding comprises
cobalt-based alloy or nickel-based alloy.
17. The valve of claim 16, wherein the alloy cladding further
comprises hard particles.
18. The valve of claim 1, wherein one or more of the legs have a
taper angle of 1-10 degrees.
19. The valve of claim 1, wherein the seal extends over a portion
of the valve seat mating surface.
20. A valve comprising: a head including a circumferential surface
and a valve seat mating surface; and a seal coupled to the
circumferential surface, wherein the seal forms an angle with the
valve seat mating surface to establish a primary seat contact area
on the seal, the primary seat contact area proximate an outer
circumferential surface of the seal.
21. The valve of claim 20, wherein the angle ranges from 5 degrees
to 30 degrees.
22. The valve of claim 21, wherein the angle ranges from 10 degrees
to 20 degrees.
23. The valve of claim 20, wherein compressive stress is
concentrated at the primary seat contact area when the valve is
mated to a valve seat.
24. The valve of claim 20, wherein the seal extends over a portion
of the valve seat mating surface.
25. A valve assembly comprising: a valve seat; and a valve in
reciprocating contact with the valve seat, the valve comprising a
head including a circumferential surface and a valve mating
surface, and leg members extending from the head, wherein thickness
of one or more of the leg members tapers in a direction away from
the head to produce laminar fluid flow around the head.
26. The valve assembly of claim 25, wherein a transition region
between an intermediate body member and the head has a radius of
curvature of 0.5 mm to 5 mm.
27. The valve assembly of claim 25, wherein one or more of the leg
members have a taper angle of 1 to 10 degrees.
28. The valve assembly of claim 25 further comprising a seal
coupled to the circumferential surface of the head.
29. The valve assembly of claim 28, wherein an exterior surface of
the seal exhibits a radius of curvature maintaining the laminar
fluid flow around the head.
30. The valve assembly of claim 28, wherein the seal forms an angle
with the valve seat mating surface to establish a primary seat
contact area on the seal where the primary seat contact area is
proximate an outer circumferential surface of the seal.
31. The valve assembly of claim 30, wherein compressive stress is
concentrated at the primary seat contact area when the valve is
mated to the seat.
32. The valve assembly of claim 30, wherein the angle ranges from
5-30 degrees.
33. The valve assembly of claim 25, wherein the valve seat
comprises a body including a first section for insertion into a
fluid passageway of a fluid end and a second section extending
longitudinally from the first section, the second section
comprising a recess in which a sintered cemented carbide inlay is
positioned, wherein the sintered cemented carbide inlay comprises a
valve mating surface and exhibits a compressive stress
condition.
34. The valve assembly of claim 33, wherein outer diameter of the
first section is equal to outer diameter of the second section.
35. A valve assembly comprising: a valve seat; and a valve in
reciprocating contact with the valve seat, the valve comprising a
head including a circumferential surface and a valve seat mating
surface, and a seal coupled to the circumferential surface, wherein
the seal forms an angle with the valve seat mating surface to
establish a primary seat contact area on the seal where the primary
seat contact area is proximate an outer circumferential surface of
the seal.
36. The valve assembly of claim 35, wherein the angle ranges from
5-30 degrees.
37. The valve assembly of claim 35, wherein compressive stress is
concentrated at the primary seat contact area when the valve is
mated to the valve seat.
38. The valve assembly of claim 35, wherein seal extends over a
portion of the valve seat mating surface.
39. The valve assembly of claim 35, wherein the valve seat
comprises a body including a first section for insertion into a
fluid passageway of a fluid end and a second section extending
longitudinally from the first section, the second section
comprising a recess in which a sintered cemented carbide inlay is
positioned, wherein the sintered cemented carbide inlay comprises a
valve mating surface and exhibits a compressive stress
condition.
40. A method of controlling fluid flow comprising: providing a
valve assembly comprising a valve seat and a valve in reciprocating
contact with the valve seat, the valve comprising a head including
a circumferential surface and a valve mating surface, and leg
members extending from the head, wherein thickness of one or more
of the leg members tapers in a direction away from the head; moving
the valve out of contact with the valve seat to flow fluid through
the valve assembly, the one or more tapered leg members inducing
laminar fluid flow around the head; and mating the valve to the
valve seat to stop fluid flow through the valve.
Description
FIELD
[0001] The present invention relates to valves and valve assemblies
and, in particular, to valves and valve assemblies for fluid end
applications.
BACKGROUND
[0002] Valves and associated valve assemblies play a critical role
in fluid ends of high pressure pumps incorporating positive
displacement pistons in multiple cylinders. Operating environments
of the valves are often severe due to high pressures and cyclical
impact between the valve body and the valve seat. These severe
operating conditions can induce premature failure and/or leakage of
the valve assembly. Moreover, fluid passing through the fluid end
and contacting the valve assembly can include high levels of
particulate matter from hydraulic fracturing operations.
Additionally, one or more acids and/or other corrosive species may
be present in the fluid/particulate mixture. In hydraulic
fracturing, a particulate slurry is employed to maintain crack
openings in the geological formation after hydraulic pressure from
the well is released. In some embodiments, alumina particles are
employed in the slurry due to higher compressive strength of
alumina relative to silica particles or sand. The particulate
slurry can impart significant wear on contact surfaces of the valve
and valve seat. Additionally, slurry particles can become trapped
in the valve sealing cycle, resulting in further performance
degradation of the valve assembly.
SUMMARY
[0003] In view of these disadvantages, valves and valve assemblies
are described herein employing architectures which can mitigate
degradative wear mechanisms, thereby prolonging life of the
assembly. In one aspect, a valve comprises a head including a
circumferential surface and a valve seat mating surface. Leg
members extend from the head, wherein thickness of one or more of
the leg members tapers in a direction away from the head to induce
laminar fluid flow around the head. The valve can also comprise a
seal coupled to the circumferential surface of the head. In some
embodiments, an exterior surface of the seal exhibits a radius of
curvature maintaining laminar fluid flow around the valve.
Additionally, the seal can overlap a portion of the valve seat
mating surface, in some embodiments.
[0004] In another aspect, a valve comprises a head including a
circumferential surface and a valve seat mating surface. A seal is
coupled to the circumferential surface, wherein the seal forms an
angle with the valve seat mating surface to establish a primary
seat contact area on the seal. The primary seat contact area can
have a location proximate an outer circumferential surface of the
seal. As described further herein, compressive stress can be
concentrated at the primary seat contact area when the valve is
mated to the valve seat. In some embodiments, the seal overlaps a
portion of the valve seat mating surface.
[0005] In another aspect, valve assemblies arc described herein. A
valve assembly, in some embodiments, comprises a valve seat and a
valve in reciprocating contact with the valve seat, the valve
comprising a head including a circumferential surface and a valve
mating surface. Leg members extend from the head, wherein thickness
of one or more of the leg members tapers in a direction away from
the head to induce laminar fluid flow around the head. The valve
can also comprise a seal coupled to the circumferential surface of
the head. In some embodiments, an exterior surface of the seal
exhibits a radius of curvature maintaining laminar fluid flow
around the valve. The seal can also overlap a portion of the valve
seat mating face, in some embodiments. Additionally, the seal can
form an angle with the valve seat mating surface to establish a
primary seat contact area on the seal. In some embodiments, the
primary seat contact area is located proximate an outer
circumferential surface of the seal. When mated to the valve seat,
the primary contact area on the seal can exhibit a concentration of
compressive stress.
[0006] The valve seat, in some embodiments, can comprise a body
including a first section for insertion into a fluid passageway of
a fluid end and a second section extending longitudinally from the
first section, the second section comprising a recess in which a
wear resistant inlay is positioned. The wear resistant inlay serves
as a valve mating surface. In some embodiments, the wear resistant
inlay exhibits a compressive stress condition. Moreover, the first
section and the second section of the valve seat can have the same
outer diameter or different outer diameters. For example, the outer
diameter of the second section can be larger than the outer
diameter of the first section. In other embodiments, the valve seat
can be formed of a single alloy composition, thereby obviating the
wear resistant inlay.
[0007] In a further aspect, methods of controlling fluid flow are
also described herein. In some embodiments, a method of controlling
fluid flow comprises providing a valve assembly comprising a valve
seat and a valve in reciprocating contact with the valve seat. The
valve comprises a head including a circumferential surface and a
valve seat mating surface. Leg members extend from the head,
wherein thickness of one or more of the leg members tapers in a
direction away from the head. The valve is moved out of contact
with the valve seat to flow fluid through the assembly, wherein the
one or more tapered leg members induce laminar fluid flow around
the head. The valve is subsequently mated with the valve seat to
stop fluid flow through the valve. In some embodiments, a seal is
coupled to the circumferential surface of the head. The seal can
have a radius of curvature maintaining laminar fluid flow around
the valve.
[0008] These and other embodiments are further described in the
following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a primary seat contact area of a seal
engaging a valve seat according to some embodiments.
[0010] FIG. 2 illustrates a stress profile of a valve seal in
contact with a valve seat according to some embodiments.
[0011] FIG. 3 illustrates an elevational view of a valve according
to some embodiments.
[0012] FIG. 4 is sectional view B of FIG. 3.
[0013] FIG. 5 is a cross-sectional view of the valve of FIG. 3
along the A-A line.
[0014] FIG. 6 is sectional view C of FIG. 5.
[0015] FIGS. 7A-7F illustrate various cross-sectional seal
geometries according to some embodiments.
[0016] FIG. 8 is fluid flow modeling of the valve in FIGS. 3-6
illustrating laminar flow around the valve head according to some
embodiments.
[0017] FIG. 9 is a cross-sectional schematic of a valve seat
according to some embodiments.
[0018] FIG. 10 is a cross-sectional schematic of a valve seat
according to some embodiments.
[0019] FIG. 11 is a bottom plan view of a valve seat according to
some embodiments.
[0020] FIG. 12 is a top plan view of a valve seat according to some
embodiments.
[0021] FIG. 13 is a perspective view of a valve seat according to
some embodiments.
[0022] FIG. 14 is a side elevational view of a valve seat according
to some embodiments.
[0023] FIG. 15 is a cross-sectional view of a sintered cemented
carbide inlay according to some embodiments.
[0024] FIG. 16 is a cross-sectional view of valve seat comprising a
sintered cemented carbide inlay coupled to an alloy body or casing
according to some embodiments.
[0025] FIG. 17 is a cross-sectional view of valve seat comprising a
sintered cemented carbide inlay coupled to an alloy body or casing
according to some embodiments.
DETAILED DESCRIPTION
[0026] Embodiments described herein can be understood more readily
by reference to the following detailed description and examples.
Elements, apparatus and methods described herein, however, are not
limited to the specific embodiments presented in the detailed
description and examples. It should be recognized that these
embodiments are merely illustrative of the principles of the
present invention. Numerous modifications and adaptations will be
readily apparent to those of skill in the art without departing
from the spirit and scope of the invention.
I. Valves
[0027] Valves are described herein employing architectures which
can mitigate degradative wear pathways, thereby prolonging life of
the valves. In one aspect, a valve comprises a head including a
circumferential surface and a valve seat mating surface. Leg
members extend from the head, wherein thickness of one or more of
the leg members tapers in a direction away from the head to induce
laminar fluid flow around the head. Leg members can have any taper
angle consistent with inducing laminar fluid flow around the head.
For example, one or more of the legs can have a taper angle of 1-10
degrees. In other embodiments, leg taper angle can be 2-5 degrees.
Leg members of the valve can exhibit the same taper angle or
differing taper angles. Taper angle of each leg member may be
individually adjusted according to the fluid flow environment of
the valve. Alternatively, taper angles of the leg members can be
adjusted in conjunction with one another to induce laminar fluid
flow around the head. Leg members may also comprise rounded and/or
flat surfaces. One or more edges of the leg members, for example,
can be rounded.
[0028] The valve can comprise any desired number of leg members.
Number of leg members can be selected according to several
considerations including, but not limited to, the fluid flow
environment of the valve and structural parameters of the assembly
incorporating the valve. A valve for, can comprise 3-6 leg members.
Leg members of the valve can exhibit equidistant radial spacing or
offset, in some embodiments. In other embodiments, radial spacing
between the leg members can be variable.
[0029] The leg members extend from the bottom surface of the valve
head. An intermediate body member or trunk may reside between the
bottom surface of the head and leg members. The leg members may
extend radially from the intermediate body member. The leg members,
in some embodiments, extend radially at an angle of 45 degrees to
80 degrees relative to the longitudinal axis of the valve. In some
embodiments, the leg members extend radially at an angle of 60-70
degrees relative the longitudinal axis of the valve. Each of the
leg members can radially extend at the same angle. Alternatively,
leg members can radially extend at different angles relative to the
longitudinal axis. Additionally, a transition region between the
bottom surface of the valve head and intermediate body member can
exhibit a radius of curvature. The radius of curvature can range
from 0.25 mm to 5 mm. In some embodiments, the transition region
radius of curvature ranges from 0.5 mm to 2 mm. The radius of
curvature can assist with maintaining laminar fluid flow around the
head.
[0030] The valve can further comprise a seal coupled to the
circumferential surface of the head. In some embodiments, the
circumferential surface defines an annular groove engaging the
seal, the annular groove comprising a top surface and bottom
surface. The top surface of the annular groove can extend radially
beyond the bottom surface. Additionally, the bottom surface of the
annular groove can transition to the valve seat mating surface. The
transition region between the groove bottom surface and the valve
seat mating surface, in some embodiments, has a radius of curvature
less than the annular groove radius of curvature.
[0031] An exterior surface of the seal can have a radius of
curvature maintaining laminar fluid flow around the valve head.
Therefore, the tapered leg members can work in conjunction with the
seal and intermediate body member to provide laminar fluid flow
around the valve head. In some embodiments, the seal overlaps a
portion of the valve seat mating surface. In other embodiments, the
seal terminates at an end wall of the valve seat mating surface and
does not overlap a portion of the valve seat mating surface. The
seal can comprise any material(s) consistent with the sealing of
valve assemblies in high pressure fluid environments, such as those
encountered in fluid ends for hydraulic fracturing operations. In
some embodiments, the seal comprises a polymeric material, such as
polyurethane or polyurethane derivative. In other embodiments, the
seal may comprise one or more elastomeric materials alone or in
combination with other polymeric materials.
[0032] Notably, the seal can form an angle (.alpha.) with the valve
seat mating surface. The angle (.alpha.) formed with the valve seat
mating surface can establish a primary area on the seal for
contacting a valve seat. Location of this primary seat contact area
can be proximate an outer circumferential surface of the seal.
Radial location of the primary seat contact area can be varied by
varying the angle (.alpha.) formed by the seal and the valve seat
mating surface. The primary seat contact area, for example, can be
moved radially outward on the seal by increasing the angle or moved
radially inward by decreasing the angle. The angle (.alpha.)
between the seal and the valve seat mating surface, for example,
can range from 5-30 degrees. In some embodiments, a value of a is
selected from Table I.
TABLE-US-00001 TABLE I Value of .alpha. (degrees) 5-25 10-20 8-15
12-17
[0033] The primary seat contact area is generally the first area of
the seal to contact the valve seat during operation of a valve
assembly employing the valve. Compressive stresses can be the
highest or concentrated in the primary seat contact area when the
valve is mated to the valve seat. By establishing a primary seat
contact area, it possible to control the stress release and/or
dissipation properties of the seal. In some embodiments, for
example, the primary seat contact area is located proximate the
outer circumferential surface of the seal. By occupying this
outward radial position, the primary seat contact area can
dissipate stress concentrations or risers quickly, due to the short
energy transfer distance to outer surface of the seal. In this way,
stress risers at interior radial locations are avoided, and seal
lifetime is enhanced. This technical solution is counter-intuitive
based on general stress management principles where stress risers
should be avoided, and stress spread evenly over the entire area of
the seal.
[0034] As described herein, the valve comprises a valve seat mating
surface. The valve seat mating surface contacts the valve seat when
a valve assembly employing the valve is in the closed position. In
some embodiments, the valve seat mating surface comprises the same
alloy forming the remainder of the valve. Alternatively, the valve
seat mating surface can comprise a wear resistant cladding. The
wear resistant cladding, for example, can comprise a wear resistant
alloy. Suitable wear resistant alloys include cobalt-based alloys
and nickel-based alloys. Cobalt-based alloy of the cladding have
compositional parameters selected from Table II, in some
embodiments.
TABLE-US-00002 TABLE II Cobalt-based alloys Element Amount (wt. %)
Chromium 5-35 Tungsten 0-35 Molybdenum 0-35 Nickel 0-20 Iron 0-25
Manganese 0-2 Silicon 0-5 Vanadium 0-5 Carbon 0-4 Boron 0-5 Cobalt
Balance
[0035] In some embodiments, cobalt-based alloy cladding has
compositional parameters selected from Table III.
TABLE-US-00003 TABLE III Co-Based Alloy Cladding Co-Based Alloy
Cladding Compositional Parameters (wt. %) 1 Co--(15-35) %
Cr--(0-35) % W--(0-20) % Mo--(0-20) % Ni--(0-25) % Fe--(0-2) %
Mn--(0-5) % Si--(0-5) % V--(0-4) % C--(0-5) % B 2 Co--(20-35) %
Cr--(0-10) % W--(0-10) % Mo--(0-2) % Ni--(0-2) % Fe--(0-2) %
Mn--(0-5) % Si--(0-2) % V--(0-0.4) % C--(0-5) % B 3 Co--(5-20) %
Cr--(0-2) % W--(10-35) % Mo--(0-20) % Ni--(0-5) % Fe--(0-2) %
Mn--(0-5) % Si--(0-5) % V--(0-0.3) % C--(0-5) % B 4 Co--(15-35) %
Cr--(0-35) % W--(0-20) % Mo--(0-20) % Ni--(0-25) % Fe--(0-1.5) %
Mn--(0-2) % Si--(0-5) % V--(0-3.5) % C--(0-1) % B 5 Co--(20-35) %
Cr--(0-10) % W--(0-10) % Mo--(0-1.5) % Ni--(0-1.5) % Fe--(0-1.5) %
Mn--(0-1.5) % Si--(0-1) % V--(0-0.35) % C--(0-0.5) % B 6 Co--(5-20)
% Cr--(0-1) % W--(10-35) % Mo--(0-20) % Ni--(0-5) % Fe--(0-1) %
Mn--(0.5-5) % Si--(0-1) % V--(0-0.2) % C--(0-1) % B
[0036] Nickel-based alloy cladding, in some embodiments, can have
compositional parameters selected from Table IV.
TABLE-US-00004 TABLE IV Nickel-based alloys Element Amount (wt. %)
Chromium 0-30 Molybdenum 0-28 Tungsten 0-15 Niobium 0-6 Tantalum
0-6 Titanium 0-6 Iron 0-30 Cobalt 0-15 Copper 0-50 Carbon 0-2
Manganese 0-2 Silicon 0-10 Phosphorus 0-10 Sulfur 0-0.1 Aluminum
0-1 Boron 0-5 Nickel Balance
[0037] In some embodiments, for example, nickel-based alloy
cladding comprises 18-23 wt. % chromium, 5-11 wt. % molybdenum, 2-5
wt. % total of niobium and tantalum, 0-5 wt. % iron, 0.1-5 wt. %
boron and the balance nickel. Alternatively, nickel-based alloy
cladding comprises 12-20 wt. % chromium, 5-11 wt. % iron, 0.5-2 wt.
% manganese, 0-2 wt. % silicon, 0-1 wt. % copper, 0-2 wt. % carbon,
0.1-5 wt. % boron and the balance nickel. Further, nickel-based
alloy cladding can comprise 3-27 wt. % chromium, 0-10 wt. %
silicon, 0-10 wt. % phosphorus, 0-10 wt.% iron, 0-2 wt. % carbon,
0-5 wt. % boron and the balance nickel.
[0038] Cobalt-based cladding and/or nickel-based cladding can be
produced by sintered powder metallurgy techniques, in some
embodiments. In other embodiments, cobalt-based claddings and
nickel-based cladding can be produced according to laser cladding
or plasma transferred arc techniques. Additionally, wear resistant
claddings for the valve mating surface can have any desired
thickness. For example, cladding thickness can be selected from
Table V.
TABLE-US-00005 TABLE V Cladding Thickness .gtoreq.50 .mu.m
.gtoreq.100 .mu.m 100 .mu.m-200 .mu.m 500 .mu.m-1 mm
[0039] Co-based or Ni-based claddings can further comprise hard
particles. In such embodiments, hard particles become trapped in
alloy matrix formed during sintering or melting of powder alloy.
Suitable hard particles can comprise particles of metal carbides,
metal nitrides, metal carbonitrides, metal borides, metal
silicides, cemented carbides, cast carbides, intermetallic
compounds or other ceramics or mixtures thereof. In some
embodiments, metallic elements of hard particles comprise aluminum,
boron, silicon and/or one or more metallic elements selected from
Groups IVB, VB, and VIB of the Periodic Table. Groups of the
Periodic Table described herein are identified according to the CAS
designation.
[0040] In some embodiments, for example, hard particles comprise
carbides of tungsten, titanium, chromium, molybdenum, zirconium,
hafnium, tantalum, niobium, rhenium, vanadium, boron or silicon or
mixtures thereof. Hard particles can also comprise nitrides of
aluminum, boron, silicon, titanium, zirconium, hafnium, tantalum or
niobium, including cubic boron nitride, or mixtures thereof.
Additionally, in some embodiments, hard particles comprise borides
such as titanium di-boride, B.sub.4C or tantalum borides or
silicides such as MoSi.sub.2 or Al.sub.2O.sub.3--SiN. Hard
particles can comprise crushed cemented carbide, crushed carbide,
crushed nitride, crushed boride, crushed silicide, or other ceramic
particle reinforced metal matrix composites or combinations
thereof. Crushed cemented carbide particles, for example, can have
2 to 25 weight percent metallic binder. Additionally, hard
particles can comprise intermetallic compounds such as nickel
aluminide.
[0041] Hard particles can have any size not inconsistent with the
objectives of the present invention. In some embodiments, hard
particles have a size distribution ranging from about 0.1 .mu.m to
about 1 mm. Hard particles can also demonstrate bimodal or
multi-modal size distributions. Hard particles can have any desired
shape or geometry. In some embodiments, hard particles have
spherical, elliptical or polygonal geometry. Hard particles, in
some embodiments, have irregular shapes, including shapes with
sharp edges.
[0042] Hard particles can be present in alloy claddings described
herein in any amount not inconsistent with the objectives of the
present invention. Hard particle loading of a cladding can vary
according to several considerations including, but not limited to,
the desired hardness, abrasion resistance and/or toughness of the
cladding. In some embodiments, hard particles are present in a
cladding in an amount of 0.5 weight percent to 40 weight percent.
Hard particles, in some embodiments, are present in a cladding in
an amount of 1 weight percent to 20 weight percent or 5 weight
percent to 20 weight percent.
[0043] The cladding, in some embodiments, is directly applied the
valve seat mating area of the valve. As described herein, the
cladding can be applied by powder metallurgical techniques,
including sintering. In other embodiments, the cladding can be
applied by laser cladding or plasma transferred arc. Alternatively,
the cladding can be provided as an inlay. The cladding, for
example, can be prefabricated to the desired dimensions as an
inlay, wherein the inlay is disposed in a recess on the valve body
to provide the valve seat mating surface. An inlay can have any of
the compositional properties described above for the valve seat
mating surface, including Co-based alloys, Ni-based alloys and/or
hard particles. A valve seat mating inlay can be press-fit and/or
metallurgically bonded to the valve body via braze alloy.
[0044] FIG. 1 illustrates the primary seat contact area of a seal
engaging a valve seat according to some embodiments. As illustrated
in FIG. 1, the primary seat contact area 11 (circled) is located
proximate or adjacent to the outer circumferential surface 12 of
the seal 10. FIG. 2 illustrates a stress profile of the seal 10
when in contact with the seat 15. Compressive stress concentration
is highest in the primary seat contact area 11, and can be quickly
dissipated through the neighboring exterior surface 12 of the seal
10.
[0045] FIG. 3 illustrates an elevational view of a valve according
to some embodiments. The valve 30 comprises a head 31 and leg
members 32 extending from the head 31. In the embodiment of FIG. 3,
three leg members 32 are present having equidistant radial spacing.
Thickness of each leg member 32 tapers in a direction away from the
head 31 to produce laminar fluid flow around the head 31. FIG. 4 is
sectional view B of FIG. 3. The taper of the leg member 32 is
evident along with rounded edges 33 of the leg members 32. The
valve of FIG. 3 also comprises a seal 34 coupled to the outer
circumferential surface of the head 31. FIG. 5 is a cross-sectional
view of the valve taken along the A-A line of FIG. 3. In the
cross-sectional view, the seal 34 engages an annular groove 35
having a top surface 35a and a bottom surface 35b. A transition
region 35c having radius of curvature R.sub.1 connects the top 35a
and bottom 35b surfaces. Moreover, the top surface 35a extends
radially beyond the bottom surface 35b. In the embodiment of FIG.
5, the bottom surface 35b transitions to the valve seat mating
surface 37 via a transition region 38 having a radius of curvature
R.sub.2. In some embodiments, R.sub.1 is greater than R.sub.2. As
described above, the valve seat mating surface 37 comprises a wear
resistant cladding 37a. In the embodiment of FIG. 3, the valve seat
mating surface 37 exhibits frustoconical geometry. The seal 34
forms an angle (.alpha.) with the valve seat mating surface 37. The
angle (.alpha.) can establish a primary seat contact area for the
seal 34, as described above. FIG. 6 is Sectional view C of FIG. 5
providing magnified detail of the annual groove 35 and associated
seal 34. The exterior surface of the seal 34a can exhibit a radius
of curvature R.sub.3 for maintaining laminar fluid flow around the
head 31.
[0046] Referring once again to FIG. 5, the leg members 32 extend
radially from an intermediate body member 39. A curved transition
region 40 having radius of curvature R.sub.3 is established between
the bottom surface of the head 31 and the intermediate body member
39. This transition region 40 can have a radius of curvature
assisting laminar fluid flow around the head 31. In other
embodiments, the transition region 40 is not curved. FIGS. 7A-7F
illustrate cross-sectional views of various seal geometries and
designs according to some embodiments.
[0047] FIG. 8 illustrates fluid flow modeling of the valve
illustrated in FIGS. 3-6. As illustrated in FIG. 8, the leg members
32 induce laminar fluid flow around the head 31. The curved
transition region 40 and the curved exterior surface 34a of the
seal 34 assist in maintaining the laminar fluid flow.
[0048] In another aspect, a valve comprises a head including a
circumferential surface and a valve seat mating surface. A seal is
coupled to the circumferential surface and forms an angle with the
valve seat mating surface to establish a primary seat contact area
on the seal. The primary seat contact area can be located proximate
an outer circumferential surface of the seal. In some embodiments,
the seal overlaps a portion of the valve seat mating surface. The
valve and associated primary seat contact area can have any
composition, properties and/or function described above in this
Section I. The valve and seal, for example, can exhibit the
architecture and function as described in FIGS. 1-8 herein.
II. Valve Assemblies
[0049] In another aspect, valve assemblies are described herein. A
valve assembly, in some embodiments, comprises a valve seat and a
valve in reciprocating contact with the valve seat, the valve
comprising a head including a circumferential surface and a valve
mating surface. Leg members extend from the head, wherein thickness
of one or more of the leg members tapers in a direction away from
the head to induce laminar fluid flow around the head. The valve
can also comprise a seal coupled to the circumferential surface of
the head. In some embodiments, an exterior surface of the seal
exhibits a radius of curvature maintaining laminar fluid flow
around the valve. The seal can also overlap a portion of the valve
seat mating face, in some embodiments. Additionally, the seal can
form an angle with the valve seat mating surface to establish a
primary seat contact area on the seal. In some embodiments, the
primary seat contact area is located proximate an outer
circumferential surface of the seal. When mated to the valve seat,
the primary contact area on the seal can exhibit a concentration of
compressive stress. Valves for use in valve assemblies can have any
architecture, properties and/or composition described in Section I
above. The valve, for example, can exhibit architecture and
function as described in FIGS. 1-8 herein.
[0050] The valve seat, in some embodiments, can comprise a body
including a first section for insertion into a fluid passageway of
the fluid end and a second section extending longitudinally from
the first section, the second section comprising a recess in which
a wear resistant inlay is positioned, wherein the wear resistant
inlay comprises a valve mating surface. In some embodiments, the
wear resistant inlay exhibits a compressive stress condition.
Moreover, the first section and the second section of the valve
seat can have the same outer diameter or different outer diameters.
For example, the outer diameter of the second section can be larger
than the outer diameter of the first section. In other embodiments,
the valve seat can be formed of a single alloy composition, thereby
obviating the wear resistant inlay.
[0051] Referring now to FIG. 9, a valve seat 10 comprises a first
section 11 for insertion into a fluid passageway of the fluid end.
In the embodiment of FIG. 9, the first section 11 comprises a
tapered outer surface 12 and an inner surface 13 that is generally
parallel to the longitudinal axis 14 of the seat 10. In some
embodiments, the inner surface 13 may also be tapered. The tapered
outer surface 12 can present a variable outer diameter D1 of the
first section 11. Alternatively, the outer surface 12 of the first
section 11 is not tapered and remains parallel to the longitudinal
axis 14. In such an embodiment, the first section 11 has a static
outer diameter D1. The outer surface 12 of the first section may
also comprise one or more recesses 15 for receiving an O-ring. One
or more O-rings can aid in sealing with the fluid passageway
wall.
[0052] A second section 16 extends longitudinally from the first
section 11. The second section has an outer diameter D2 that is
larger than outer diameter D1 of the first section 11. In the
embodiment of FIG. 9, a ring 19 encasing the second section 16
forms part of the outer diameter D2. In some embodiments, the ring
19 can account for the second section 16 having an outer diameter
greater than the first section 11. In such embodiments, the body of
the valve seat can be cylindrical, where the addition of the ring
19 provides the second section 16 the larger outer diameter D2.
Alternatively, as illustrated in FIGS. 9 and 10, the second section
16 independent of the ring 19 can have an outer diameter D2 greater
than the outer diameter D1 of the first section.
[0053] A shoulder 17 is formed by the larger outer diameter D2 of
the second section 16. In the embodiment of FIG. 9, the shoulder
surface 17a is generally normal to the longitudinal axis 14 of the
valve seat 10. In other embodiments, the shoulder surface 17a can
taper and/or form an angle with the longitudinal axis having a
value of 5-70 degrees. Design of the shoulder 17 can be selected
according to several considerations including, but not limited to,
entrance geometry of the fluid passageway and pressures experienced
by the seat when in operation. In some embodiments, for example,
taper of the shoulder can be set according to curvature of the
fluid passageway entrance engaging the shoulder. The first section
11 transitions to the second section 16 at a curved intersection
18. The curved intersection can have any desired radius. Radius of
the curved intersection, in some embodiments, can be 0.05 to 0.5
times the width of the shoulder. In other embodiments, a curved
transition is not present between the first and second sections.
Moreover, in some embodiments, the outer diameter (D2) of the
second section (16) is equal or substantially equal to the outer
diameter (D1) of the first section (11) (e.g. D1 32 D2).
[0054] The second section 16 also comprises a frusto-conical valve
mating surface 20, wherein the second section 16 is encased by a
ring 19. In the embodiment of FIG. 9, the ring 19 is coupled to the
outer surface of the second section 16 in a concentric arrangement.
The ring 19 imparts a compressive stress condition to the second
section 16. By placing the second section 16 in compressive stress,
the ring 19 can assist in balancing or equalizing stress between
the first section 11 and second section 16 when the first section
11 is press fit into a fluid passageway of the fluid end. A
compressive stress condition can also inhibit crack formation
and/or propagation in the second section 16, thereby enhancing
lifetime of the valve seat and reducing occurrences of sudden or
catastrophic seat failure. A compressive stress condition may also
enable the use of harder and more brittle materials in the second
section 16, such as harder and more wear resistant grades of
cemented carbide forming the valve mating surface.
[0055] In the embodiment of FIG. 9, the ring 19 forms a planar
interface with the outer surface or perimeter of the second section
16. In other embodiments, the ring 19 may comprise one or more
protrusions or flanges residing on the inner annular surface of the
ring 19. A protrusion or flange on the inner ring surface may fit
into a recess or groove along the perimeter of the second section
16. This structural arrangement can assist in proper engagement
between the ring 19 and second section 16. This structural
arrangement may also assist in retaining the second section 16
within the ring 19 during operation of the fluid end. In a further
embodiment, the second section 16 can comprise one or more
protrusions of flanges for engaging one or more recesses in the
interior annular surface of the ring 19.
[0056] FIG. 10 is a schematic illustrating another embodiment of a
valve seat described herein. The valve seat of FIG. 10 comprises
the same structural features illustrated in FIG. 9. However, the
ring 19 in FIG. 10 at least partially covers the shoulder 17. The
ring 19, for example, can be provided a radial flange 19a for
interfacing the shoulder 17 of the second section 16. In some
embodiments, the ring 19 fully covers the shoulder 17. FIG. 11 is a
bottom plan view of a valve seat having the architecture of FIG.
10. As illustrated in FIG. 11, the ring 19 is coupled to the
perimeter of the second section and partially covers the shoulder
17. FIG. 12 is a top plan view of a valve seat having the
architecture of FIG. 10. The frusto-conical valve mating surface 20
transitions into the bore 21 of the valve seat 10. The ring 19
encases the second section 16, imparting a compressive stress
condition to the second section 16. Accordingly, a compressive
stress condition is imparted to the valve mating surface 20, which
can assist in resisting crack formation and/or crack propagation in
the mating surface 20. Moreover, FIG. 13 illustrates a perspective
view of the valve seat of FIG. 10. FIG. 14 illustrates a side
elevational view of a valve seat according to some embodiments,
wherein a curved intersection does not exist between the first
section 11 and second section 16.
[0057] As described herein, the valve seat can comprise sintered
cemented carbide. In some embodiments, the first and second section
of the valve seat are each formed of sintered cemented carbide.
Alternatively, the first section can be formed of metal or alloy,
such as steel or cobalt-based alloy, and the second section is
formed of sintered cemented carbide. Forming the second section of
sintered cemented carbide can impart hardness and wear resistance
to the valve mating surface relative to other materials, such as
steel.
[0058] In some embodiments, the second section is formed of a
composite comprising sintered cemented carbide and alloy. For
example, a sintered cemented carbide inlay can be coupled to a
steel substrate, wherein the sintered cemented carbide inlay forms
a portion or all of the valve mating surface, and the steel
substrate forms the remainder of the second section. In such
embodiments, the sintered carbide inlay can extend radially to
contact the ring encasing the second section, thereby permitting
the ring to impart a compressive stress condition to the sintered
carbide inlay. In other embodiments, the steel or alloy substrate
comprises a recess in which the sintered carbide inlay is
positioned. In this embodiment, the outer rim of the recess is
positioned between the sintered carbide inlay and ring, wherein
compressive stress imparted by the ring is transmitted through the
outer rim to the sintered carbide inlay.
[0059] Sintered cemented carbide of the valve seat can comprise
tungsten carbide (WC). WC can be present in the sintered carbide in
an amount of at least 70 weight percent or in an amount of at least
80 weight percent. Additionally, metallic binder of cemented
carbide can comprise cobalt or cobalt alloy. Cobalt, for example,
can be present in the sintered cemented carbide in an amount
ranging from 3 weight percent to 20 weight percent. In some
embodiments, cobalt is present in sintered cemented carbide of the
valve seat in an amount ranging from 5-12 weight percent or from
6-10 weight percent. Further, sintered cemented carbide valve seat
may exhibit a zone of binder enrichment beginning at and extending
inwardly from the surface of the substrate. Sintered cemented
carbide of the valve seat can also comprise one or more additives
such as, for example, one or more of the following elements and/or
their compounds: titanium, niobium, vanadium, tantalum, chromium,
zirconium and/or hafnium. In some embodiments, titanium, niobium,
vanadium, tantalum, chromium, zirconium and/or hafnium form solid
solution carbides with WC of the sintered cemented carbide. In such
embodiments, the sintered carbide can comprise one or more solid
solution carbides in an amount ranging from 0.1-5 weight
percent.
[0060] In some embodiments, a single grade of sintered cemented
carbide can be employed to form the first and second sections of
the valve seat. In other embodiments, one or more compositional
gradients can exist between sintered cemented carbide of the first
section and second section. For example, sintered cemented carbide
of the first section may have larger average grain size and/or
higher metallic binder content to increase toughness. In contrast,
sintered cemented carbide of the second section may have smaller
average grain size and less binder for enhancing hardness and wear
resistance. Additionally, a compositional gradient can exist within
the first and/or second section of the valve seat. In some
embodiments, sintered cemented carbide forming the valve mating
surface comprises small average grain size and lower metallic
binder content for enhancing hardness and wear resistance.
Progressing away from the valve mating surface, the sintered
cemented carbide composition of the second section can increase in
grain size and/or binder content to enhance toughness and fracture
resistance. In some embodiments, for example, sintered cemented
carbide of high hardness and high wear resistance can extend to a
depth of 50 .mu.m-1 mm or 75-500 .mu.m in the second section. Once
the desired depth is reached, the sintered cemented carbide
composition changes to a tougher, fracture resistant
composition.
[0061] When the valve mating surface is formed of sintered cemented
carbide, the sintered cemented carbide can have surface roughness
(R.sub.a) of 1-15 .mu.m, in some embodiments. Surface roughness
(R.sub.a) of the sintered cemented carbide can also be 5-10 .mu.m.
Surface roughness of sintered cemented carbide forming the valve
mating surface may be obtained via mechanical working including,
but not limited to, grinding and/or blasting techniques. Moreover,
sintered cemented carbide forming the second section of the valve
seat, including the valve mating surface, can exhibit a compressive
stress condition of at least 500 MPa. In some embodiments, sintered
cemented carbide forming the second section can have a compressive
stress condition selected from Table I.
TABLE-US-00006 TABLE VI Sintered Cemented Carbide Compressive
Stress (GPa) .gtoreq.1 .gtoreq.1.5 .gtoreq.2 0.5-3 1-2.5
Compressive stress condition of the sintered cemented carbide can
result from compression imparted by the ring encasing the second
section and/or mechanically working the sintered cemented carbide
to provide a valve mating surface of desired surface roughness.
Compressive stress of the sintered cemented carbide may be
determined via X-ray diffraction according to the Sin.sup.2.psi.
method. Sintered cemented carbide of the valve seat may also
exhibit hardness of 88-94 HRA.
[0062] The ring encasing the second section can be formed of any
suitable material operable to impart a compressive stress condition
to the second section. In some embodiments, the ring is formed of
metal or alloy, such as steel. The ring may also be formed of
ceramic, cermet and/or polymeric material, such as
polyurethane.
[0063] In another aspect, a valve seat comprises a first section
for insertion into a fluid passageway of a fluid end and a second
section extending longitudinally from the first section, the second
section including a frusto-conical valve mating surface comprising
sintered cemented carbide having surface roughness (R.sub.a) of
1-15 .mu.m. In some embodiments, the sintered cemented carbide of
the valve mating surface is provided as an inlay ring coupled to a
metal or alloy body. In other embodiments, the second section is
formed of the sintered cemented carbide. The second section can
have an outer diameter greater than the outer diameter of the first
section. Alternatively, the outer diameters of the first and second
sections are equal or substantially equal. Moreover, the second
section of the valve seat may optionally be encased by a ring as
described herein.
[0064] In another aspect, a valve seat for use in a fluid end
comprises a body including a first section for insertion into a
fluid passageway of the fluid end and a second section extending
longitudinally from the first section. The second section comprises
a recess in which a sintered cemented carbide inlay is positioned,
wherein the sintered cemented carbide inlay comprises a valve
mating surface and exhibits a compressive stress condition. In some
embodiments, the sintered cemented carbide inlay has surface
roughness (R.sub.a) of 1-15 .mu.m. FIG. 15 illustrates a sintered
cemented carbide inlay according to some embodiments. The sintered
cemented carbide inlay 70 comprises a frusto-conical valve mating
surface 71. Sintered cemented carbide forming the inlay 70 can have
any composition and/or properties described above. The sintered
cemented carbide inlay can be coupled to a metal or alloy body or
casing. The metal or alloy body can form the first section of the
valve seat and a portion of the second section. FIG. 16 is a
cross-sectional view of valve seat comprising a sintered cemented
carbide inlay coupled to an alloy body or casing according to some
embodiments. In the embodiment of FIG. 16, the alloy body 82 forms
the first section 81 of the valve seat 80 for insertion into a
fluid passageway of a fluid end. The alloy body 82 also forms a
portion of the second section 86 and defines a recess 83 in which
the sintered cemented carbide inlay 70 is positioned. As in FIG.
15, the sintered cemented carbide inlay 70 comprises a
frusto-conical valve mating surface 71 having surface roughness of
(R.sub.a) of 1-15 .mu.m. In some embodiments, R.sub.a of the valve
mating surface 71 is 5-10 .mu.m. The sintered cemented carbide
inlay 70 can be coupled to the alloy body 82 by any desired means
including brazing, sintering, hot isostatic pressing and/or press
fit. In some embodiments, the inner annular surface of the alloy
body in the second section 86 comprises one or more protrusions for
engaging a groove on the perimeter of the sintered cemented carbide
inlay 70. In some embodiments, the alloy body 82 can impart a
compressive stress condition to the sintered cemented carbide inlay
70. The second section 86 of the alloy body 82, for example, can
impart a compressive stress condition to the sintered cemented
carbide inlay 70. The sintered cemented carbide inlay 70 can
exhibit compressive stress having a value selected from Table I
above, in some embodiments. The alloy body 82 can be formed of any
desired alloy including, but not limited to, steel and cobalt-based
alloy. In the embodiment of FIG. 16, the alloy body 82 provides a
portion of the second section 86 having an outer diameter D2
greater than the outer diameter D1 of the first section 81. The
outer diameter D1 may vary with taper of the outer surface 84 of
the first section 81, in some embodiments. A curved intersection 88
exists at the transition of the first section 81 and the second
section 86. Additionally, the larger outer diameter D2 of the
second section 86 creates a shoulder 87. The shoulder 87 may have a
construction as described in FIGS. 9-10 herein. In other
embodiments, outer diameter D1 the first section 81 and outer
diameter D2 of the second section 86 are equal or substantially
equal. In such embodiments where D1 equals D2, the outer surface 84
of the body 82 can be cylindrical.
[0065] As described herein, the first and second sections of a
valve seat can have the same outer diameter or substantially the
same outer diameter. In such embodiments, the valve seat exhibits a
single outer diameter in contrast to the dual outer diameters (D1,
D2) of the valve seat illustrated in FIG. 16. FIG. 17 illustrates a
single outer diameter valve seat comprising a sintered cemented
carbide inlay according to some embodiments. The reference numerals
in FIG. 17 correspond to the same components as in FIG. 16. As
illustrated in FIG. 17, the valve seat 80 comprises single outer
diameter, D1. In some embodiments, the valve seat 80 does not
employ an inlay 70 of sintered cemented carbide or other wear
resistant material. The valve mating surface, for example, can be
formed of the same alloy as the remainder of the seat body. In some
embodiments, a wear resistant cladding can be applied to alloy of
the valve mating surface. The wear resistant cladding can comprise
cobalt-based or nickel-based alloys described herein or metal
matrix composite materials. In further embodiments, the outer
diameter of the valve seat may taper in a direction away from the
valve mating surface. The first section of the seat, for example,
may have a larger outer diameter than the second section. However,
a shoulder is not present between the first and second sections,
and the outer diameter tapers linearly inward. Wear resistant
inlays or claddings can also be used in embodiments where the outer
diameter of the valve seat tapers without establishing a
shoulder.
III. Fluid Flow Control
[0066] In a further aspect, methods of controlling fluid flow are
also described herein. In some embodiments, a method of controlling
fluid flow comprises providing a valve assembly comprising a valve
seat and a valve in reciprocating contact with the valve seat. The
valve comprises a head including a circumferential surface and a
valve seat mating surface. Leg members extend from the head,
wherein thickness of one or more of the leg members tapers in a
direction away from the head. The valve is moved out of contact
with the valve seat to flow fluid through the assembly, wherein the
one or more tapered leg members induce laminar fluid flow around
the head. The valve is subsequently mated with the valve seat to
stop fluid flow through the valve. In some embodiments, a seal is
coupled to the circumferential surface of the head. The seal can
have a radius of curvature maintaining laminar fluid flow around
the valve. The valve and valve seat of the assembly can have any
architecture, composition and/or properties described in Sections I
and II above. The valve and valve seat, for example, can exhibit
the architecture and function as described in FIGS. 1-17
herein.
[0067] Various embodiments of the invention have been described in
fulfillment of the various objectives of the invention. It should
be recognized that these embodiments are merely illustrative of the
principles of the present invention. Numerous modifications and
adaptations thereof will be readily apparent to those skilled in
the art without departing from the spirit and scope of the
invention.
* * * * *